Dr. Sutapa Ghosh - Academia.edu (original) (raw)

Papers by Dr. Sutapa Ghosh

Astrophysics and Space Science, 2015

We have investigated some of the properties of dense sub-nuclear matter at the crustal region (bo... more We have investigated some of the properties of dense sub-nuclear matter at the crustal region (both the outer crust and the inner crust region) of a magnetar. The relativistic version of Thomas-Fermi (TF) model is used in presence of strong quantizing magnetic field for the outer crust matter. The compressed matter in the outer crust, which is a crystal of metallic iron, is replaced by a regular array of spherically symmetric Wigner-Seitz (WS) cells. In the inner crust region, a mixture of iron and heavier neutron rich nuclei along with electrons and free neutrons has been considered. Conventional Harrison-Wheeler (HW) and Bethe-Baym-Pethick (BBP) equation of states are used for the nuclear mass formula. A lot of significant changes in the characteristic properties of dense crustal matter, both at the outer crust and the inner crust, have been observed. Comment: 20 pages, 11 .eps figures, to appear in EPJA

International Journal of Modern Physics D, 2002

An expression for the electrical conductivity at the core of a magnetar is derived using Boltzman... more An expression for the electrical conductivity at the core of a magnetar is derived using Boltzmann kinetic equation with the relaxation time approximation. The rates for the relevant scattering processes, e.g., electron–electron and electron–proton scattering processes are evaluated in presence of strong quantizing magnetic fields using tree level diagrams. It is found that in the presence of a strong quantizing magnetic field, electrical conductivity behaves like a second rank tensor. However, if the zeroth Landau levels are only level occupied by the charged particles, it again behaves like a scalar of a one-dimensional system.

Physical Review C, 2007

The breaking of chiral symmetry of light quarks at zero temperature in presence of strong quantiz... more The breaking of chiral symmetry of light quarks at zero temperature in presence of strong quantizing magnetic field is studied using Nambu-Jona-Lasinio (NJL) model with Thomas-Fermi type semi-classical formalism. It is found that the dynamically generated light quark mass can never become zero if the Landau levels are populated and the mass of light quarks increases with the increase of magnetic field strength.

The breaking of chiral symmetry of light quarks at zero temperature in presence of strong quantiz... more The breaking of chiral symmetry of light quarks at zero temperature in presence of strong quantizing magnetic field is studied using Nambu-Jona-Lasinio (NJL) model with Thomas-Fermi type semi-classical formalism. It is found that the dynamically generated light quark mass can never become zero if the Landau levels are populated and increases with the increase of magnetic field strength.

Modern Physics Letters A, 2003

It is shown explicitly that a ferromagnetic transition of neutron star (NS)/proto-neutron star (P... more It is shown explicitly that a ferromagnetic transition of neutron star (NS)/proto-neutron star (PNS) matter in the β-equilibrium condition with σ-ω-ρ exchange type of mean field approximation can actually occur if and only if the neutrinos remain trapped within the system, and perhaps it is also necessary for the neutrinos/anti-neutrinos to carry some finite nonzero mass. It is further shown that the electrons also play a significant role in this transition process. It is therefore, very much unlikely that such a transition of spin polarization can really take place in old neutron stars of very low temperature, whereas, the possibility of spontaneous ferromagnetic transition cannot be ruled out in a newly born PNS.

Modern Physics Letters A, 2002

It is shown that electron gas in dense stellar matter exhibit super-fluid (frictionless) like pro... more It is shown that electron gas in dense stellar matter exhibit super-fluid (frictionless) like property if the magnetic field strength is high enough to populate only the zeroth Landau levels, i.e. it is possible that at the core of a magnetar, the proton matter behaves like a superconductor, neutron matter behaves like a super-fluid and electron gas shows super-fluidity without superconductivity. Therefore, the core region as a whole of a magnetar may behave like a frictionless matter which is quite surprising.

Astrophysics and Space Science, 2009

Following some of the recent articles on hole super-conductivity and related phenomena by Hirsch ... more Following some of the recent articles on hole super-conductivity and related phenomena by Hirsch [1, 2, 3], a simple model is proposed to explain the observed low surface magnetic field of the expected quark stars. It is argued that the diamagnetic moments of the electrons circulating in the electro-sphere induce a magnetic field, which forces the existing quark star magnetic flux density to become dilute. We have also analysed the instability of normal-superconducting interface due to excess accumulation of magnetic flux lines, assuming an extremely slow growth of superconducting phase through a first order bubble nucleation type transition.

Physical Review C, 2006

Using the relativistic version of Landau theory of Fermi liquid with σ − ω and ρ mesons exchange,... more Using the relativistic version of Landau theory of Fermi liquid with σ − ω and ρ mesons exchange, we have obtained an equation state for dense neutron star matter in presence of strong quantizing magnetic field. It is found that in this scenario the self-energies of both neutron and proton components of dense neutron star matter become complex under certain physical conditions. To be more specific, it is observed that in the exchange diagrams of σ, ω and neutral ρ transfer processes and in the direct interaction diagram with ρ± transfer reactions, the nucleon self-energies become complex in nature.

Modern Physics Letters A, 2017

In this paper, we have investigated the Thomas–Fermi model for the electron gas in Rindler space.... more In this paper, we have investigated the Thomas–Fermi model for the electron gas in Rindler space. We have observed that if the uniform acceleration is along [Formula: see text]-direction, then there is [Formula: see text]-symmetry in space. For the sake of mathematical simplicity, we have therefore assumed a two-dimensional spatial structure [Formula: see text] in Rindler space. It has been shown that in two-dimensional spatial coordinates, the electrons are distributed discontinuously but in a periodic manner in a number of rectangular strip-like domains along [Formula: see text]-direction. Some of them are having void structure, with no electrons inside such rectangular strips, while some are filled up with electrons. We call the latter type domain as the normal zone. We have also given physical interpretation for such exotic type electron distribution in Rindler space.

Pramana, May 1, 2003

It is explicitly shown that if phase transition occurs at the core of a newborn neutron star with... more It is explicitly shown that if phase transition occurs at the core of a newborn neutron star with moderately strong magnetic field strength, which populates only the electron's Landau levels, then in the β-equilibrium condition, the quark core is energetically much more unstable than the neutron matter of identical physical condition.

Modern Physics Letters A, Nov 23, 2015

In this article we have developed a formalism to obtain the Schrödinger equation for a particle i... more In this article we have developed a formalism to obtain the Schrödinger equation for a particle in a frame undergoing an uniform acceleration in an otherwise flat Minkowski space-time geometry. We have presented an exact solution of the equation and obtained the eigenfunctions and the corresponding eigenvalues. It has been observed that the Schrödinger equation can be reduced to an one dimensional hydrogen atom problem. Whereas, the quantized energy levels are exactly identical with that of an one dimensional quantum harmonic oscillator. Hence considering transitions, we have predicted the existence of a new kind of quanta, which will either be emitted or absorbed if the particles get excited or de-excited respectively.

The European Physical Journal A, Jun 17, 2010

We have investigated some of the properties of dense sub-nuclear matter at the crustal region (bo... more We have investigated some of the properties of dense sub-nuclear matter at the crustal region (both the outer crust and the inner crust region) of a magnetar. The relativistic version of Thomas-Fermi (TF) model is used in presence of strong quantizing magnetic field for the outer crust matter. The compressed matter in the outer crust, which is a crystal of metallic iron, is replaced by a regular array of spherically symmetric Wigner-Seitz (WS) cells. In the inner crust region, a mixture of iron and heavier neutron rich nuclei along with electrons and free neutrons has been considered. Conventional Harrison-Wheeler (HW) and Bethe-Baym-Pethick (BBP) equation of states are used for the nuclear mass formula. A lot of significant changes in the characteristic properties of dense crustal matter, both at the outer crust and the inner crust, have been observed.

Annals of Physics, Mar 1, 2009

The effect of strong quantizing magnetic field on the equation of state of matter at the outer cr... more The effect of strong quantizing magnetic field on the equation of state of matter at the outer crust region of magnetars is studied. The density of such matter is low enough compared to the matter density at the inner crust or outer core region. Based on the relativistic version of semi-classical Thomas-Fermi-Dirac model in presence of strong quantizing magnetic field a formalism is developed to investigate this specific problem. The equation of state of such low density crustal matter is obtained by replacing the compressed atoms/ions by Wigner-Seitz cells with nonuniform electron density. The results are compared with other possible scenarios. The appearance of Thomas-Fermi induced electric charge within each Wigner-Seitz cell is also discussed.

arXiv (Cornell University), Jul 23, 2002

It is shown explicitly that if only the zeroth Landau level is occupied by electrons in strongly ... more It is shown explicitly that if only the zeroth Landau level is occupied by electrons in strongly magnetized neutron star matter in β-equilibrium, then both the proton and neutron matter sectors become spin symmetric. Whereas, the study of Pauli para-magnetism of neutron matter sector shows that such a scenario is physically impossible. It is also shown that in dense stellar hadronic matter in β-equilibrium in presence of strong quantizing magnetic field, with σ −ω −ρ exchange type mean field interaction and with the inclusion of magnetic dipole moments does not allow electrons to occupy only the zeroth Landau level.

Annals of Physics, 2009

The effect of strong quantizing magnetic field on the equation of state of matter at the outer cr... more The effect of strong quantizing magnetic field on the equation of state of matter at the outer crust region of magnetars is studied. The density of such matter is low enough compared to the matter density at the inner crust or outer core region. Based on the relativistic version of semi-classical Thomas-Fermi-Dirac model in presence of strong quantizing magnetic field a formalism is developed to investigate this specific problem. The equation of state of such low density crustal matter is obtained by replacing the compressed atoms/ions by Wigner-Seitz cells with nonuniform electron density. The results are compared with other possible scenarios. The appearance of Thomas-Fermi induced electric charge within each Wigner-Seitz cell is also discussed.

Annals of Physics, 2004

An exact formalism for the relativistic version of Landau theory of Fermi liquid in presence of s... more An exact formalism for the relativistic version of Landau theory of Fermi liquid in presence of strong quantizing magnetic field is developed. Both direct and exchange type interactions with scalar and vector coupling cases are considered.

Astrophysics and Space Science, 2015

We have investigated some of the properties of dense sub-nuclear matter at the crustal region (bo... more We have investigated some of the properties of dense sub-nuclear matter at the crustal region (both the outer crust and the inner crust region) of a magnetar. The relativistic version of Thomas-Fermi (TF) model is used in presence of strong quantizing magnetic field for the outer crust matter. The compressed matter in the outer crust, which is a crystal of metallic iron, is replaced by a regular array of spherically symmetric Wigner-Seitz (WS) cells. In the inner crust region, a mixture of iron and heavier neutron rich nuclei along with electrons and free neutrons has been considered. Conventional Harrison-Wheeler (HW) and Bethe-Baym-Pethick (BBP) equation of states are used for the nuclear mass formula. A lot of significant changes in the characteristic properties of dense crustal matter, both at the outer crust and the inner crust, have been observed. Comment: 20 pages, 11 .eps figures, to appear in EPJA

International Journal of Modern Physics D, 2002

An expression for the electrical conductivity at the core of a magnetar is derived using Boltzman... more An expression for the electrical conductivity at the core of a magnetar is derived using Boltzmann kinetic equation with the relaxation time approximation. The rates for the relevant scattering processes, e.g., electron–electron and electron–proton scattering processes are evaluated in presence of strong quantizing magnetic fields using tree level diagrams. It is found that in the presence of a strong quantizing magnetic field, electrical conductivity behaves like a second rank tensor. However, if the zeroth Landau levels are only level occupied by the charged particles, it again behaves like a scalar of a one-dimensional system.

Physical Review C, 2007

The breaking of chiral symmetry of light quarks at zero temperature in presence of strong quantiz... more The breaking of chiral symmetry of light quarks at zero temperature in presence of strong quantizing magnetic field is studied using Nambu-Jona-Lasinio (NJL) model with Thomas-Fermi type semi-classical formalism. It is found that the dynamically generated light quark mass can never become zero if the Landau levels are populated and the mass of light quarks increases with the increase of magnetic field strength.

The breaking of chiral symmetry of light quarks at zero temperature in presence of strong quantiz... more The breaking of chiral symmetry of light quarks at zero temperature in presence of strong quantizing magnetic field is studied using Nambu-Jona-Lasinio (NJL) model with Thomas-Fermi type semi-classical formalism. It is found that the dynamically generated light quark mass can never become zero if the Landau levels are populated and increases with the increase of magnetic field strength.

Modern Physics Letters A, 2003

It is shown explicitly that a ferromagnetic transition of neutron star (NS)/proto-neutron star (P... more It is shown explicitly that a ferromagnetic transition of neutron star (NS)/proto-neutron star (PNS) matter in the β-equilibrium condition with σ-ω-ρ exchange type of mean field approximation can actually occur if and only if the neutrinos remain trapped within the system, and perhaps it is also necessary for the neutrinos/anti-neutrinos to carry some finite nonzero mass. It is further shown that the electrons also play a significant role in this transition process. It is therefore, very much unlikely that such a transition of spin polarization can really take place in old neutron stars of very low temperature, whereas, the possibility of spontaneous ferromagnetic transition cannot be ruled out in a newly born PNS.

Modern Physics Letters A, 2002

It is shown that electron gas in dense stellar matter exhibit super-fluid (frictionless) like pro... more It is shown that electron gas in dense stellar matter exhibit super-fluid (frictionless) like property if the magnetic field strength is high enough to populate only the zeroth Landau levels, i.e. it is possible that at the core of a magnetar, the proton matter behaves like a superconductor, neutron matter behaves like a super-fluid and electron gas shows super-fluidity without superconductivity. Therefore, the core region as a whole of a magnetar may behave like a frictionless matter which is quite surprising.

Astrophysics and Space Science, 2009

Following some of the recent articles on hole super-conductivity and related phenomena by Hirsch ... more Following some of the recent articles on hole super-conductivity and related phenomena by Hirsch [1, 2, 3], a simple model is proposed to explain the observed low surface magnetic field of the expected quark stars. It is argued that the diamagnetic moments of the electrons circulating in the electro-sphere induce a magnetic field, which forces the existing quark star magnetic flux density to become dilute. We have also analysed the instability of normal-superconducting interface due to excess accumulation of magnetic flux lines, assuming an extremely slow growth of superconducting phase through a first order bubble nucleation type transition.

Physical Review C, 2006

Using the relativistic version of Landau theory of Fermi liquid with σ − ω and ρ mesons exchange,... more Using the relativistic version of Landau theory of Fermi liquid with σ − ω and ρ mesons exchange, we have obtained an equation state for dense neutron star matter in presence of strong quantizing magnetic field. It is found that in this scenario the self-energies of both neutron and proton components of dense neutron star matter become complex under certain physical conditions. To be more specific, it is observed that in the exchange diagrams of σ, ω and neutral ρ transfer processes and in the direct interaction diagram with ρ± transfer reactions, the nucleon self-energies become complex in nature.

Modern Physics Letters A, 2017

In this paper, we have investigated the Thomas–Fermi model for the electron gas in Rindler space.... more In this paper, we have investigated the Thomas–Fermi model for the electron gas in Rindler space. We have observed that if the uniform acceleration is along [Formula: see text]-direction, then there is [Formula: see text]-symmetry in space. For the sake of mathematical simplicity, we have therefore assumed a two-dimensional spatial structure [Formula: see text] in Rindler space. It has been shown that in two-dimensional spatial coordinates, the electrons are distributed discontinuously but in a periodic manner in a number of rectangular strip-like domains along [Formula: see text]-direction. Some of them are having void structure, with no electrons inside such rectangular strips, while some are filled up with electrons. We call the latter type domain as the normal zone. We have also given physical interpretation for such exotic type electron distribution in Rindler space.

Pramana, May 1, 2003

It is explicitly shown that if phase transition occurs at the core of a newborn neutron star with... more It is explicitly shown that if phase transition occurs at the core of a newborn neutron star with moderately strong magnetic field strength, which populates only the electron's Landau levels, then in the β-equilibrium condition, the quark core is energetically much more unstable than the neutron matter of identical physical condition.

Modern Physics Letters A, Nov 23, 2015

In this article we have developed a formalism to obtain the Schrödinger equation for a particle i... more In this article we have developed a formalism to obtain the Schrödinger equation for a particle in a frame undergoing an uniform acceleration in an otherwise flat Minkowski space-time geometry. We have presented an exact solution of the equation and obtained the eigenfunctions and the corresponding eigenvalues. It has been observed that the Schrödinger equation can be reduced to an one dimensional hydrogen atom problem. Whereas, the quantized energy levels are exactly identical with that of an one dimensional quantum harmonic oscillator. Hence considering transitions, we have predicted the existence of a new kind of quanta, which will either be emitted or absorbed if the particles get excited or de-excited respectively.

The European Physical Journal A, Jun 17, 2010

We have investigated some of the properties of dense sub-nuclear matter at the crustal region (bo... more We have investigated some of the properties of dense sub-nuclear matter at the crustal region (both the outer crust and the inner crust region) of a magnetar. The relativistic version of Thomas-Fermi (TF) model is used in presence of strong quantizing magnetic field for the outer crust matter. The compressed matter in the outer crust, which is a crystal of metallic iron, is replaced by a regular array of spherically symmetric Wigner-Seitz (WS) cells. In the inner crust region, a mixture of iron and heavier neutron rich nuclei along with electrons and free neutrons has been considered. Conventional Harrison-Wheeler (HW) and Bethe-Baym-Pethick (BBP) equation of states are used for the nuclear mass formula. A lot of significant changes in the characteristic properties of dense crustal matter, both at the outer crust and the inner crust, have been observed.

Annals of Physics, Mar 1, 2009

The effect of strong quantizing magnetic field on the equation of state of matter at the outer cr... more The effect of strong quantizing magnetic field on the equation of state of matter at the outer crust region of magnetars is studied. The density of such matter is low enough compared to the matter density at the inner crust or outer core region. Based on the relativistic version of semi-classical Thomas-Fermi-Dirac model in presence of strong quantizing magnetic field a formalism is developed to investigate this specific problem. The equation of state of such low density crustal matter is obtained by replacing the compressed atoms/ions by Wigner-Seitz cells with nonuniform electron density. The results are compared with other possible scenarios. The appearance of Thomas-Fermi induced electric charge within each Wigner-Seitz cell is also discussed.

arXiv (Cornell University), Jul 23, 2002

It is shown explicitly that if only the zeroth Landau level is occupied by electrons in strongly ... more It is shown explicitly that if only the zeroth Landau level is occupied by electrons in strongly magnetized neutron star matter in β-equilibrium, then both the proton and neutron matter sectors become spin symmetric. Whereas, the study of Pauli para-magnetism of neutron matter sector shows that such a scenario is physically impossible. It is also shown that in dense stellar hadronic matter in β-equilibrium in presence of strong quantizing magnetic field, with σ −ω −ρ exchange type mean field interaction and with the inclusion of magnetic dipole moments does not allow electrons to occupy only the zeroth Landau level.

Annals of Physics, 2009

The effect of strong quantizing magnetic field on the equation of state of matter at the outer cr... more The effect of strong quantizing magnetic field on the equation of state of matter at the outer crust region of magnetars is studied. The density of such matter is low enough compared to the matter density at the inner crust or outer core region. Based on the relativistic version of semi-classical Thomas-Fermi-Dirac model in presence of strong quantizing magnetic field a formalism is developed to investigate this specific problem. The equation of state of such low density crustal matter is obtained by replacing the compressed atoms/ions by Wigner-Seitz cells with nonuniform electron density. The results are compared with other possible scenarios. The appearance of Thomas-Fermi induced electric charge within each Wigner-Seitz cell is also discussed.

Annals of Physics, 2004

An exact formalism for the relativistic version of Landau theory of Fermi liquid in presence of s... more An exact formalism for the relativistic version of Landau theory of Fermi liquid in presence of strong quantizing magnetic field is developed. Both direct and exchange type interactions with scalar and vector coupling cases are considered.